Atherosclerosis 211 (2010) 467–470 Contents lists available at ScienceDirect Atherosclerosis journal homepage: www.elsevier.com/locate/atherosclerosis Impact of coronary calcium on arterial age and coronary heart disease risk estimation using the MESA arterial age calculator  Jamalah A. Munir ∗ , Hongyan Wu, Kelly Bauer, Jody Bindeman, Carole Byrd, Patrick O’Malley, Allen J. Taylor Department of Medicine and Cardiology Service, Walter Reed Army Medical Center, Washington, DC, United States article info Article history: Received 29 January 2010 Received in revised form 5 March 2010 Accepted 8 March 2010 Available online 16 March 2010 Keywords: Prevention Risk factors Atherosclerosis abstract Background: We evaluated the impact of arterial age calculation on reclassification of global coronary heart disease risk using the Framingham risk score. Methods: We applied CHD risk factor data from the Prospective Army Coronary Calcium Project to the MESA arterial age calculator (available at http://www.mesa-nhlbi.org). Subjects (N = 1998) were studied with measured CHD risk factors and electron beam computed tomography for the identification of coro- nary artery calcium. Framingham risk scores (FRS), using the 10-year CHD risk model with and without arterial age, were calculated using the MESA arterial age calculator. Results: The mean FRS of the cohort (42.9 ± 2.7 years, male gender 82%) was 4.5 ± 3.6%. Coronary calcium was present in 394 subjects (19.7%). Application of the arterial age calculator increased mean age from 42.9 ± 2.7 to 43.6 ± 10.4 years (P < .001), and the mean FRS increased from 4.5 ± 3.6 to 7.3 ± 8.1% (P < .001). Reclassification was seen primarily among male subjects, in whom the mean age (chronological vs. arterial age) increased from 42.9 ± 2.7 to 44.2 ± 11.0 (P < .001) and the prevalence of high CHD risk increased from 0.6% (10 of 1639) to 10% (165 of 1639; P < .001). Conclusion: Among healthy individuals ages 40–50, application of the MESA arterial age calculator reclas- sifies 1 in 10 men from low to intermediate risk and 1 in 15 men from low to high risk. Published by Elsevier Ireland Ltd. Global coronary heart disease (CHD) risk scores form the foun- dation of the initial evaluation of an individuals’ cardiovascular risk [1], though these risk prediction models do not identify all who are at risk. As a result, there remains a considerable gap in detection of asymptomatic individuals who eventually develop CHD [2]. Among proposed methods to close the “detection gap”, imaging techniques can be used to identify subclinical atherosclerosis. In particular, coronary artery calcium (CAC) can incrementally predict risk of future CHD events [3]. Integration of CAC within a global risk score has been proposed using the concept of arterial age via adjustment  Disclaimer: The views expressed in this article are those of the author and do not necessarily reflect the official policy or position of the Department of the Army, Department of Defense, nor the U.S. Government. We certify that all individuals who qualify as authors have been listed; each has participated in the conception and design of this work, the analysis of data (when applicable), the writing of the document, and the approval of the submission of this version; that the document represents valid work; that if we used information derived from another source, we obtained all necessary approvals to use it and made appropriate acknowledgements in the document; and that each takes public responsibility for it. ∗ Corresponding author at: Cardiology Service, Walter Reed Army Medical Cen- ter, 6900 Georgia Ave, NW, Building 2, Room 4A27, Washington, DC 20307, United States. Tel.: +1 202 782 9856; fax: +1 202 782 7063. E-mail address: Jamalah.munir@amedd.army.mil (J.A. Munir). of the age of the patient on the basis of their level of atheroscle- rosis. However, understanding whether such an approach leads to an efficient reclassification of risk is a necessary conceptual first step in the development of this approach. The Multi-Ethnic Study in Atherosclerosis (MESA) investigators recently published [4] and developed a web-based calculator for the computation of arterial age. Calculated as a linear function of the log transformed CAC, one approach to evaluating the utility of this calculator can be through an analysis of the proportion of patients whose risk assessment is reclassified using arterial versus chronological age. We examined the impact of arterial age on the reclassification of CHD risk estima- tion within the Prospective Army Coronary Calcium (PACC) Study cohort. 1. Methods The PACC Study is a prospective cohort study to define the rela- tionships between CAC, risk factors, and CHD outcomes. A detailed description of the study design and methods has been published previously [5]. The study was approved by the Department of Clin- ical Investigation and Human Use Committee of Walter Reed Army Medical Center. Briefly, all active duty Army personnel, ages 39–50 years old, and stationed within the National Capital Area of the Wal- 0021-9150/$ – see front matter. Published by Elsevier Ireland Ltd. doi:10.1016/j.atherosclerosis.2010.03.016